A major focus of sensory physiology has been describing how stimuli in the environment are encoded and initially processed in the primary sensory areas. However, little is known about how these signals are transformed into information useful for subsequent areas involved in making decisions. The proposed project will examine the relationship between visual perception and real-time optical imaging signals recorded from populations of neurons of the primary visual cortex (V1), while monkeys perform a visual detection task near psychophysical threshold. The extent to which behavioral choices can be predicted from the V1 population response will be determined. In addition, the trial-by-trial relationship between spontaneous cortical activity and evoked cortical activity will be determined, as well as the extent to which choices can be predicted from the spontaneous population activity. Finally, top-down signals in V1 will be investigated with a detection task that includes spatial uncertainty, and will be quantitatively compared to the monkey's behavior. This work will shed light on how perceptual signals are ultimately used by the brain, which is vital for research on brain-machine interface technologies for individuals with perceptual deficits.